The white whale tasks me

So, there's this heron that lives around by us, and I often see him/her on the old canal, or by the Taff, or as here, by a stream. Yet I never manage to capture a photo of him. Twice today he took off majestically just as I got my camera out. And then he went and hid behind a tree, taunting me. I feel I am becoming quite Ahab like in my quest to capture him.